This study reports the synthesis of tail-shaped alginate particles using a microfluidic platform combined with a sedimentation strategy. By utilizing microfluidic emulsification in the cross-junction channel, the formation of regular droplets was achieved. Following a facile and convenient sedimentation process and an ionic crosslinking process, sodium-alginate droplets became tail-shaped and then gradually developed into calcium-alginate microparticles. The effects of the concentration of the CaCl(2) crosslinker and the viscosity of the alginate solution on the shape and/or size of the particles were further investigated. The proposed synthesis methodology has the advantages of actively controlling the tail-shape formation, having a narrow size distribution, as well as being a facile and convenient process with a high throughput. This approach can be applied to many applications in the pharmaceutical and biomedical arena.

This study reports a facile method for the synthesis of hemispherical and discoidal chitosan microparticles by a combination of microfluidic technology and gelation strategy at an oil/water interface. Utilizing microfluidic emulsification in a cross-junction channel, the formation of regular droplets was achieved. Following the ionic gelation procedure at the liquid-liquid interface of the gelling solution and oil solution in the reservoir pool, either hemispherical or discoidal chitosan microparticles were obtained. Special emphasis was put on the interface reaction of emulsion gelation parameters such as ionic crosslinkers, density modifiers, and surfactants, to tailor the morphologies of chitosan particles ranging from 160 to 750 μm. In addition, the proposed microfluidic device is capable of generating relatively uniform microparticles with a well-controllable shape and size. Being a simple, low-cost and high-throughput process is an added advantage. The synthesized hemispherical and discoidal chitosan microparticles can be applied to many applications in the pharmaceutical and biomedical arena.